|1.||a plant disease characterized by a superficial white powdery growth on stems and leaves, caused by parasitic ascomycetous fungi of the family Erysiphaceae: affects the rose, aster, apple, vine, oak, etc|
|2.||any of the fungi causing this disease|
|powdery mildew (pou'də-rē) Pronunciation Key
Any of various important plant diseases caused by fungi, especially those of the family Erysiphaceae, which produce powdery conidia on the surface of the hosts leaves and stems.
plant disease of worldwide occurrence, caused by many specialized races of fungal species in the genera Erysiphe, Microsphaera, Phyllactinia, Podosphaera, Sphaerotheca, and Uncinula. Hundreds of species of trees, shrubs, vines, flowers, vegetables, fruits, grasses, field crops, and weeds can be affected by powdery mildew.
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